Kees Cook ef40d28f17 randomize_kstack: Remove non-functional per-arch entropy filtering ... An unintended consequence of commit 9c573cd313 ("randomize_kstack: Improve entropy diffusion") was that the per-architecture entropy size filtering reduced how many bits were being added to the mix, rather than how many bits were being used during the offsetting. All architectures fell back to the existing default of 0x3FF (10 bits), which will consume at most 1KiB of stack space. It seems that this is working just fine, so let's avoid the confusion and update everything to use the default. The prior intent of the per-architecture limits were: arm64: capped at 0x1FF (9 bits), 5 bits effective powerpc: uncapped (10 bits), 6 or 7 bits effective riscv: uncapped (10 bits), 6 bits effective x86: capped at 0xFF (8 bits), 5 (x86_64) or 6 (ia32) bits effective s390: capped at 0xFF (8 bits), undocumented effective entropy Current discussion has led to just dropping the original per-architecture filters. The additional entropy appears to be safe for arm64, x86, and s390. Quoting Arnd, "There is no point pretending that 15.75KB is somehow safe to use while 15.00KB is not." Co-developed-by: Yuntao Liu <liuyuntao12@huawei.com> Signed-off-by: Yuntao Liu <liuyuntao12@huawei.com> Fixes: 9c573cd313 ("randomize_kstack: Improve entropy diffusion") Link: https://lore.kernel.org/r/20240617133721.377540-1-liuyuntao12@huawei.com Reviewed-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390 Link: https://lore.kernel.org/r/20240619214711.work.953-kees@kernel.org Signed-off-by: Kees Cook <kees@kernel.org>		2024-06-20 11:34:46 -07:00
..
boot	TTY/Serial changes for 6.10-rc1	2024-05-22 11:53:02 -07:00
configs	USB / Thunderbolt changes for 6.10-rc1	2024-05-22 11:40:09 -07:00
crypto	crypto: arm64/aes-ce - Simplify round key load sequence	2024-04-26 17:26:09 +08:00
hyperv	x86/hyperv: Use Hyper-V entropy to seed guest random number generator	2024-03-18 22:01:52 +00:00
include	Jeff Xu's implementation of the mseal() syscall.	2024-05-24 12:47:28 -07:00
kernel	randomize_kstack: Remove non-functional per-arch entropy filtering	2024-06-20 11:34:46 -07:00
kvm	Kbuild updates for v6.10	2024-05-18 12:39:20 -07:00
lib	arm64: crypto: use CC_FLAGS_FPU for NEON CFLAGS	2024-05-19 14:36:18 -07:00
mm	The usual shower of singleton fixes and minor series all over MM,	2024-05-19 09:21:03 -07:00
net	Modules changes for v6.10-rc1	2024-05-15 14:05:08 -07:00
tools	arm64: errata: Add workaround for Arm errata 3194386 and 3312417	2024-05-10 12:21:57 +01:00
xen
Kbuild
Kconfig	arm64 fixes for -rc1	2024-05-23 12:09:22 -07:00
Kconfig.debug
Kconfig.platforms	Updates for the interrupt subsystem:	2024-05-14 09:47:14 -07:00
Makefile	arm64: implement ARCH_HAS_KERNEL_FPU_SUPPORT	2024-05-19 14:36:18 -07:00